Benefit Plans - Additional Information (Detail) - Defined Benefit Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Matching contribution by the company to the plan	100.00%
Percentage of employees' eligible compensation	6.00%
Defined contribution plan, general and administrative expenses	$ 0.2	$ 0.2

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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